Story highlights

Until now, Priorities USA has spent the 2016 election cycle entirely focused on getting Clinton elected

The push would likely start next week, and last three weeks until Election Day

Washington (CNN)The leading super PAC trying to elect Hillary Clinton is preparing to expand beyond the presidential race and potentially run television ads focused on a handful of competitive Senate races.

Until now, Priorities USA has spent the 2016 election cycle entirely focused on the top of the ticket -- getting Clinton elected. The fact that they may use their resources to also promote Democratic candidates in down-ballot races suggests how increasingly confident they are in a Clinton victory.

According to a source familiar with the plans, Priorities USA is currently producing television ads to potentially air in Senate contests in North Carolina, Nevada, New Hampshire and Pennsylvania -- all competitive races that are also battleground states for the presidential race.

Other Senate races could also be targeted, and potentially even some top-tier House seats that Democrats think they have a shot at taking from Republicans.

Although plans are still being finalized, the push would likely start next week, and last three weeks until Election Day.

Read More

Officials at Priorities USA have been polling in Senate and House races over the last month to see "if an opportunity presented itself," according to the source familiar with the super PAC's plans.

Guy Cecil, the chairman of Priorities USA, is the former executive director of the Democratic Senatorial Campaign Committee, which helps elect Democrats to the Senate. One of his former bosses, Sen. Chuck Schumer, would become majority leader if Democrats take control of the Senate.